Ortony, Julia H., Baofu Qiao, Christina J. Newcomb, Timothy J. Keller, Liam C. Palmer, Elad Deiss-Yehiely, Monica Olvera de la Cruz, Songi Han, and Samuel I. Stupp. “Water Dynamics from the Surface to the Interior of a Supramolecular Nanostructure.” Journal of the American Chemical Society 139, no. 26 (July 5, 2017): 8915–21.
Water within and surrounding the structure of a biological system adopts context-speciﬁc dynamics that mediate virtually all of the events involved in the inner workings of a cell. These events range from protein folding and molecular recognition to the formation of hierarchical structures. Water dynamics are mediated by the chemistry and geometry of interfaces where water and biomolecules meet. Here we investigate experimentally and computationally the translational dynamics of vicinal water molecules within the volume of a supramolecular peptide nanoﬁber measuring 6.7 nm in diameter. Using Overhauser dynamic nuclear polarization relaxometry, we show that drastic diﬀerences exist in water motion within a distance of about one nanometer from the surface, with rapid diﬀusion in the hydrophobic interior and immobilized water on the nanoﬁber surface. These results demonstrate that water associated with materials designed at the nanoscale is not simply a solvent, but rather an integral part of their structure and potential functions.